Reciprocating knife can opener



Nov. 6 1923. 1,473,306

J. T. M GRATH RECIPROCATING KNIFE CAN OPENER Filed Ana. 6. 1921 PatentedNov. 6, 1923.

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JOHN THOMAS MCGRATH, or nroorrmerou, ILLINOIS.

REC-IPBOCATING KNIFE CAN OPENER.

Application filed August 6, 1921. Serial No. 490,429.

had to the accompan in drawin s and to a n b the characters of refs neemarked thereon, which form a part of this specification.

T his invention relates to improvements in can openers of that typewhich is provided with a reciprocating knife by which to sever the canend or top from the body, so that the can end or top may be wholly orpartially removed to discharge the contents through the opening formedby the partial or entire removal of the top wall or head of the can.

My improvements are herein shown as adapted to a type of machine inwhichthe knife is carried by a reciprocating part that is mounted forreciprocation at a given station, and wherein the can itself is turnedon a support therefor below theknife sothat successive areas of the canmay be presented to the action of the cutting knife by feed movement ofthe can. In this respect the machine is adapted to open cans ofdifferent cross sections, as cylindric cans, square cans, oblong cans,and the like, inasmuch as the can may be readily directed to the singleoperating position of the cutting knife.

Among the objects of the invention is to provide an exceedingly simple,efiicient, and durable and rapidly operable can opening machine which iscapable of adjustment to operate on cans of different heights, and

which is also capable of operating on cans of varying cross sections.

A further ob ect of the inventlon 1s to provide an improved mounting forthe cutting knife by which the said knife can be adjusted to round orsquare. cans, and in this respect said machine is provided with a knifeholder, to which the knife can be fixed thereon as a straight cuttingknife for cut t ng the heads of oblong or square cans, and is alsoconstructed with means to permit the body of the knife to be curved sothat the trailingcutting edge of the knife can be curved inwardlytowards the can center when operating on round or oval cans and thusenable'the knife to cut closely to the edge of the can. head whileavoiding an an gular position thereof that .would cut through the seamby which the can head is locked: to the can body.

A further object of, the invention isto-provide-a novel means forsupporting and guiding the knife holder on a bracket which. isconstructed to vertically reciprocate the holder in straight directionthrough the medium of a swinging operating handle.

Another object of the invention is to'pro- I 'vide in a machine havingthese chara'cteris tics, means for adjusting the height ofthebracketrelatively to the standard which supports thesame, and therebyadapt themachine to'cans of different heights.

A further object of the invention is to provide a novel'gui'de or gaugefor u e in connection with round cans, adjustable to hold cans ofdiflerent diameters in proper relation to the cutting knife.

I Further objects of the invention are to improve and simplifycanopeners, and the invention consists in the combination and arrangementof the parts shown in the drawings and described in the specification,andis pointed out in the appended claims.

In the drawings-z Figure l is a side elevation of a can opener embodyingmy invention, showingin section the vertical table or support for thecan. Figure 2 is an enlarged section taken on the line 22'of Figure 1.

Figure 3 is a horizontal section taken on the line 3.3 of Figure 1.

Figures e and 5 are horizontal sections on the line -l 4 of Figure 1,showing the parts in different positions of adjustment.

F ignre 6 is. a. perspective view of the reciprocating knife holder. IFigure 7 is aperspectiveview of the cutter knife-when adjusted tooperate on round cans, showing a portion of the can in dotted lines. p

As shown in the drawings, 10 designates a standard that may be fastenedtoth 'e-ledgeof a table or like'support 11 by a suitable form of jawclamp 12,.having a clamping screw 13. The table 11 constitutes asupport'for the can C, Whose head or end Q is adapted to be cut to 0en'the can. 14 designates a bracket; that 11s slidably mounted to thestandard 10 for vertical adjustment of the bracket relatively to thesupport 11, and

said bracket can be locked to the standard in different verticalpositions by a locking screw of any suitable form.

16 designates a vertically reciprocating plunger which is adapted toslide in a verti cal opening 17 at the inner end of the bracket whichoverhangs the can to be opened. Said plunger is arovided on its lowerend with a knife supporting head 18 which can be made of any suitableshape at its sides and rear end. In accordance with one phase of theinvention, the inner .ace 19 of the knife supporting head is laterallyconcave to form at the corners of the head at each side of the concaveportion relative sharp knife supporting edges 19. Said concave face isprovided with one or more threaded openings 20 to receive cutting knifelocking screws, will hereinafter more fully appear. Said headis furtherprovided with a downwardly facing shoulder 21 adapted to bear againstthe upper edge of the cutting knife.

The said plunger 16 is surrounded by a spiral expansion spring 22 whichis interposed between the upper face of the bracket 14 and an abutment23 formed by a cap fixed to the upper end, of the plunger. The tendencyof said spring is to hold said plunger upwardly with the knife carriedthereby above its cutting position. 24 designates a plunger operatinglever which is hinged to a horizontal pin 25 that is fixed in the outerend of the bracket 2%. Said handle extends inwardly over the can supportto afford the required leverage to operate the reciprocating knifesupporting plunger. 26 designates a link which is hinged at its lowerend, as by means of a pin 27, to a part of the hand lever 24 abreast thebracket 14.. Said link is also hinged at its upper end, as by means of apin 28, to "the upper end of the plunger 16, said pin extending throughan opening in the upper end of the plunger and through registeringopenings of the hollow abutment 23, which latter is made tubular to fitdown over the top of the plunger. The lower portion or skirt 30 of saidabutment is made of somewhat larger internal diameter than the externaldiameter of the plunger to receive the upper end of thespring 22, asshown in Figure 2, which said spring bears at its lower end squarelyagainst the apertured guide bracket 14; for the plunger.

32 designates a cutting knife which is adapted to be clamped on theconcave face .19 of the head by means of a screw or screws 33 whichextend loosely through openings in the body of the knife and into andare threaded in tlie'tlii'eaclecL opening or openings 20 of the knifesupporting head. The said knife is so adjusted to the head that itsupper edge bears againstthe downwardly facing shoulder 21 formed on theinner side 'to the height of the can.

of the head above the concave Portion 19 thereof, so as to therebyrelieve the screw or screws 33 of shearing strains when the knifedepressed to cut the can head. Said knife is formed with a lower,cutting point 35, an advance cutting edge 36, and a trailing cuttingedge 37 somewhat longer than the advance cutting edge. Said cuttingedges are formed by beveling the rear margins of the knife.

When cutting straight marginal portions of square or oblong cans, theknife 32 is adjusted to the position shown in Figure That is to say, theclamping pressure of the screw or screws 33 and the elasticity of theblade will be suiiicient to hold the rear margins of the knife againstthe edges 19 of the concave face of the head 18. With this adjustment ofthe knife, a square or oblong can placed on the support 11, with thecutting knife in line with that portion of the can head to be cut orsevered, and the height of the knife mounting is properly adjusted Theplunger is then forced downwardly by the hand lever 24: to force theknife through the can head, and upon release of the hand lever thespring 22 raises the knife supporting plunger and knife away from thecan so as to permit the can to be advanced along in a straight line topresent another portion of the margin thereof to the action of theknife, this operation being continued throughout the straight side of anoblong or rectangular can. The can is then turned on the support 11 tobring the adjacent margin under the knife and these operations arecontinued until the can head is completely severed, or sufiicientlysevered to pull the same away from the can body to empty the contentsthrough the opening formed by cutting the head away;

When operating on round or oval cans, the clamping screw or screws 33are turned inwardly sufiicientto curve the cutting knife along itsmedian vertical, axis in the manner shown in Figures 5' and 7. 'Suchdeformation of the blade at the point where it is borne upon by the heador heads of the clamping screw orlscrews 33 or other suitable curvingmeans, is carried throughout the length of the blade so to thereby curvethe cutting end of the knife in the manner shown in Figure 7, or withthe trailing cutting edgev 37 turned inwardly towards the center ofthecan head; a By thus vertically curving the cutting knife the trailingcutting edge thereof will be turned inwardly beyond the adjacent seam ofthe can that joins the body and head so as to enable the knife to severthe can head closely adjacent to said seam without striking the latter.It will be understood from what has been said that if the cutting knifewere in the adjustment shown in Figure 4, when cutting'the head of 'iiia round or oval can, the round head-of the can could not be severedclose to its margin, without the trailing edge of the knife striking thelock seam between the head and body. Therefore, to use a straight knifeadjustment, as is shown in "Figure 4, the head would necessarily need tobe cut or severed an objectionable distance inwardly from the lock seam.With the adjustment shown in Fignre however, andwhichis made possible bycurving the inner face of the knife head and using a resilient blade,the cutting point of the knife may be made to attack the margin of thehead closely adjacent to the lock seam, while at the same time avoidingthe trailing edge of the knife encountering said seam.

When the machine is operatin t on round cans, it will be desirable toprovide a guiding gauge of such character as to permit the can to bereadily turned by hand on the vertical axis of the can. Such gauge isshown in Figures 1 and 3. It comprises a. curved bearing shoe 4O struckon an arc to correspond with the average size round an, and providedwith outwardly extending lock and guide arms 41, 42, which are adaptedto extend through horizontal openings in lugs 43, 44, formed on thelower end of the standard 10. The said gauge member thus constructed maybe locked in adjusted positions by means of a set screw 45 that isthreaded through one of the lugs 44 and against the corresponding arm 41of the gauge. Thus the gauge can be readily adjusted towards and fromthe center of the can and can be fixedly locked by reason of the setscrew and of the guiding engagement of the parallel arms in the guidelugs 43, 44.

It will be noted that I have provided a very simple, effective, light,and yet durable construction and one which may be said to be universal,in that it can be operated to open both round and square cans. Thedetails of the construction whereby the functions set forth areeffected, may be varied within the spirit and scope of the claims heretoappended, and the invention, therefore, is not l'nnited to theparticular construction shown except as specifically set out in theappended claims and as imposed by the prior art.

I claim:

1. A can opener comprising a standard having means to fir; it to asupport, a bracket vertically adjustable on said standard, and providedat its inner end with a plunger bearing. with means to lock it invertical adjustment on said standard, a plunger slidable in said bearingand provided below said bearing with a knife mounting head. and abovesaid bearing with an abutment, a spiral spring surrounding theplungerbetween said bracket and said abutment to hold said head upwardlyagainst the bracket,

a lever pivoted to said bracket, and a link connected to said lever andextending there from for'connection to said plunger 2. A can openercomprising a. st: having means to fix it to a support, bracketvertically adjustable on said standard, and provided at its inner endwith a plunger bearing, with means to lock it in vertical adjustment onsaid standard. a plunger slidable in said bearing and provided belowsaid bearing with a knife mounting head, and above said bearing with anabutment, a spiral spring surrounding the plunger between said bracketand said abutment to hold said head upwardly against the bracket, alever pivoted to said bracket, and a link connected to said lever andex-- tending upwardly therefrom for connection to the upper end of saidplunger, said abutment having a depending skirt portion which enclosesthe upper end'ot said spring.

3. A can opener comprising a standard having means to fix it to asupport, a bracket adjustable on said standard, and provided at itsinner end with a plunger bearing, with means to lock it in verticaladjustment on said standard, a plunger slidable in said bearing andprovided below said. bearing with a knife mounting head, and above saidbearing with an abutment, a spiral spring surrounding the plungerbetween said bracket and said abutment to hold said head upwardlyagainst the bracket, a lever pivoted to said bracket for operating saidplunger, and a can gauge carried by and extending laterally from thelower end of saidstands ard and having locking means to adapt it to endof the standard, and having a concave face against which the can is heldwhile turning it to present new areas of the can headto the cuttingknife. 1

5. A can opener comprising a standard. having means to it to asupport,'a bracket vertically adjustable thereon by means to lock itfixed to the standard to overhang the support, a reciprocating. guidedplunger supported 7 on said bracket and provided with a knife head,means for reciprocating .said plunger. and a round can gauge adjustably'mounted on the lower end of the standard, said gauge comprising a curvedbearer member and parallel locking and guiding arms operatively &

supported at the base of said standard, lugs at the base. of the plungerthrough which said arms are adapted to slide, and a set screw piercingone of said lu s and imping- 5 ing against one of said arms.

6. A can opener comprising a a bracket fixed thereto a reciprocating,guided plunger supported on said bracket and provided with a knife head,means for reciprocating said plunger; and a round can gauge comprising acurved bezner parallel arms, lugs at the base of the plunger throughwhich said arms are adapted to slide and means for lOCking one of saidarms to one of said lugs.

7. In a can opening machine, a knife support, formed with a concave faceflank-l by backing edges, a resilient knife adap l to span said concaveface and rest against said edges and having an off-center point flankedby cutting edges. and pressure means to fasten said knife on saidsupport, said means bearing against the portion of the knife opposite tosaid concave face to hold the knife against said edges and acting;

increased pressure to concave said knife towards said face ane to therebdeform said cutting edges.

8. The combination with a knife niounting, and a resilient blade having.a cutting point, an advance cutting edge and a lone trailing edge, ofmeans to fasten the l i on said support, said fastening means ating totransversely curve said 7 through its cutting edge to cause the traninyedge to be curved towards the advance cutting edge.

9. in a can opener, a transversel" wincave knife mounting having laterallznfic backing edges flanking a transverselv curved face, a knife andthreaded means to pierce the longitudinal center of said knife to fastenthe knife flativise on the mounting; and adapted to be threaded into thedeeper part of the curved face of the mounting to transversely curvesaid knife.

In Witness whereof I claim the foregoing as my invention, 1 hereuntoappend my nature this 27 day of duly 1921.

JOHN THOMAS? MQGRATK?

